Elmer? Y' got your ears on? Anybody well versed in SDR willing to share your knowledge?

[namedpipes]

I've got two of the little buggars, one is a Chinese clone I used for years to scrape readings from my electric and gas meters. The other I picked up, branded as a FlightAware device, although it appears to be just a regular SDR inside a pretty shell. I'll look up the part numbers. Both function with SDR#. I have an assortment of "general use" compact antennas from my Baofeng plus the tuned 1090 antenna.

These are the two devices:

Amazon product ASIN B00PDM76ZWView: https://www.amazon.com/gp/product/B00PDM76ZW
(shows as Generic RTL2832U OEM)
Amazon product ASIN B01M7REJJWView: https://www.amazon.com/gp/product/B01M7REJJW
(shows as Generic RTL2832U)

Depending on conditions, I can "sometimes" tune a very strong commercial FM station and hear scraps of contact at various frequencies. Nothing reliable or clear, but it is "trying". I feel like a better antenna would help more than replacing the receiver dongles. If I can receive reliably, I'd like to build up a Raspberry driven P25 monitor for the New Hampshire trunk systems and more generally, see what it can pick up around the world and in orbit.

What is a good antenna recommendation, compatible with these, for "usually" 2 meter reception? I don't suppose I could use my old Dish TV antenna for L band...

And can this muttly pair be used for P25 trunk listening or should I be looking at current SDR devices? Perhaps they've gotten better in recent years.

I'm a General, but with little applied experience. Most of my radio background is 20 years back and more on the monitoring side than Ham, plus a little super specialized stuff tracking things. So, hopefully I can keep up with the conversation, but no practical clue on how, say, trunks work with P25 systems.

 

[ToddDubya]

Dipole or roll up j-pole?

 

[Kevin_NH]

I've got two of the little buggars, one is a Chinese clone I used for years to scrape readings from my electric and gas meters. The other I picked up, branded as a FlightAware device, although it appears to be just a regular SDR inside a pretty shell. I'll look up the part numbers. Both function with SDR#. I have an assortment of "general use" compact antennas from my Baofeng plus the tuned 1090 antenna.

Manchester Makerspace is about to announce 1-day classes on RTL-SDR, and this will cover antenna choice, etc.

can this muttly pair be used for P25 trunk listening or should I be looking at current SDR devices? Perhaps they've gotten better in recent years.

In the Sub-$100 price range, the differences are mostly better quality parts, a 1PPM temperature compensated TCXO, upgraded R820T2 tuner etc.

 

[Baby Billy]

The flight aware device has a built in filter, no? I wouldn't expect to be able to do much with it except receive ADS-B.

You may be able to use the other one for P25 if the frequencies on the system you are trying to listen to are close enough that they fall within the bandwidth limitations of the SDR (2.4 Mhz?). But you will likely need an additional one (or two?).

 

[namedpipes]

I wound up ordering a pair of Nooelec RTL-SDR bundles and they're functionally a bit better than either the FA or the other. With a higher antenna I may get decent reception.

I'm somewhat high in elevation but there are large hills and small mountains surrounding me. Even the AM/FM is sketchy.